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This question gets asked quite often so I thought it would be useful to see what the majority consider a safe level of knock count of their PFC.
Poll: What knock count do you see on your Apexi Power FC
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never seen over 20 on mine
john
john
Generaly on an EVO Power FCnianlala said:
A knock of 25 - 30 would be a small ping in the earphones and not much to worry about if it was on a stock ECU with knock controll, it wouldn't be enough to run it in the High detonation Table's
a knock of 40 - 50 is getting to the stage where you need to gett it checked. any thing over 60 is definatly a problem and needs looking at, any thing over 80 stop right ther dont drive it on boost.
What Kind of Knock count are you seeing?
And when does it occure?
Regards Matt
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never seen more than 12-14 on mine 
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I can truthly tell you on a bone stock engine anything between 0-35 is genrally not serious knock, When mapping mine I can hear the onset of knock around 38 then by say 45-50 it would be audibly knock in the det cans.
If you have a forged engine then things can change as the standard knock sensor can pick up phantom knock etc, without a set of det cans to check against then it really is hard to say. To be safe keep it below 35 or 30 for real safety.
If you have a forged engine then things can change as the standard knock sensor can pick up phantom knock etc, without a set of det cans to check against then it really is hard to say. To be safe keep it below 35 or 30 for real safety.
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Re: Re: Poll: What knock count do you see on your Apexi Power FC
82 yesterday
82 yesterday
Matt TRL said:
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Between cars, models and mods the baseline noise varies.
On an individual car the RPM determines the sensible level of knock count, so a 20 at low RPM where you might normally have 5 for example is more significant than a 25 at high RPM when you might normally have 20. Knock analysis based on a single value for the entire RPM range is misleading.
Also, what is more important is not the actual raw level of knock, but how it compares to the previous sample - ie do you have a sudden spike. A sudden spike in a knock sensor tracing is far more specific for knock than a gradual increase in noise.
The OEM ECU actually compares the present knock sensor value with the previous one to detect such spikes and does well with this method. This is why coming onto boost can give a trivial knock sum where there is no real knock because there is a sudden change in engine noise as the turbo spools up.
On an individual car the RPM determines the sensible level of knock count, so a 20 at low RPM where you might normally have 5 for example is more significant than a 25 at high RPM when you might normally have 20. Knock analysis based on a single value for the entire RPM range is misleading.
Also, what is more important is not the actual raw level of knock, but how it compares to the previous sample - ie do you have a sudden spike. A sudden spike in a knock sensor tracing is far more specific for knock than a gradual increase in noise.
The OEM ECU actually compares the present knock sensor value with the previous one to detect such spikes and does well with this method. This is why coming onto boost can give a trivial knock sum where there is no real knock because there is a sudden change in engine noise as the turbo spools up.
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Re: Re: Re: Re: Poll: What knock count do you see on your Apexi Power FC
Full whack in 4th gear at a sprint - Curbrough
I also got a 75 at full whack in 5th gear - on a private road of course
Went back to see matt, he adjusted the timing later on in the rev range. I've just been out and cained the balls off it and got a 22. All sorted now
Full whack in 4th gear at a sprint - Curbrough
I also got a 75 at full whack in 5th gear - on a private road of course
Went back to see matt, he adjusted the timing later on in the rev range. I've just been out and cained the balls off it and got a 22. All sorted now
MikeyG said:
Re: Re: Re: Re: Re: Poll: What knock count do you see on your Apexi Power FC
Good stuff kenny mate. Im having the same done next week at TRL. did you notice any power decrease after Matt tweaked it? Do you think you have done any damage?kenny1 said:Full whack in 4th gear at a sprint - Curbrough
I also got a 75 at full whack in 5th gear - on a private road of course
Went back to see matt, he adjusted the timing later on in the rev range. I've just been out and cained the balls off it and got a 22. All sorted now
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Re: Re: Re: Re: Re: Re: Poll: What knock count do you see on your Apexi Power FC
there is a little decrease on the graph further up the rev range but nothing you can feel. It goes like **** and feels better than I expected. It has the potential for a lot more but don't want to risk the rods going for a walk. As for damage...i doubt it.
there is a little decrease on the graph further up the rev range but nothing you can feel. It goes like **** and feels better than I expected. It has the potential for a lot more but don't want to risk the rods going for a walk. As for damage...i doubt it.
MikeyG said:
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I had a PFC in a 7 mapped to 1.6 by RC and found the harder you drove it the less likely you were to see any significant number say 20ish, but ocasionally when you tried to load it up from low speed in 3rd or 4th you would see it go higher maybe 30-45ish.
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